JP2007000821A - Treatment system of calcium mass-containing organic waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for treating calcium mass together with organic wastes with a low load on environments. <P>SOLUTION: Calcium mass C is separated from calcium mass C-containing organic wastes A and after the separation, the organic wastes A are decomposed into biogas G and digested liquid D by methane fermentation and the separated calcium mass C is loaded to a storage tank 2 together with an aqueous high-pressure solution of carbon dioxide CO<SB>2</SB>in the biogas G and/or the digested liquid D. Alternatively, calcium mass C-containing organic wastes A are loaded to a storage tank 2 together with an aqueous high-pressure solution of carbon dioxide CO<SB>2</SB>to dissolved the calcium mass C and the organic wastes A remaining after the dissolution are decomposed into biogas G and digested liquid D by methane fermentation and the carbon dioxide CO<SB>2</SB>in the biogas G and/or the digested liquid D may be turned back to the storage tank 2 for reuse. As the storage tank 2, a deep layer type storage tank 2a in which pressure sufficient to dissolve carbon dioxide CO<SB>2</SB>in the bottom end is obtained can be used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a system for treating organic waste containing calcium lumps, and more particularly to a system for treating organic waste containing calcium lumps such as shells, eggshells, vertebrate bones, and crab shells.

For example, in a thermal / nuclear power plant, as shown in FIG. 3, shellfish such as mussels, oysters, barnacles, etc. grow and accumulate in the seawater intake facility 23 and block the intake facility 23. Because of this, it is scraped off periodically and treated as waste. Such shellfish waste is generated in large quantities in harbor facilities and fisheries processing plants, but the separation of shellfish and shellfish is cumbersome, so conventionally it was left undisturbed until the shellfish decomposed or incinerated as it is. Often disposed of. However, because of the high moisture content of shellfish waste, it is necessary to input energy such as heavy oil in order to incinerate significantly and generate a large amount of carbon dioxide (CO ₂ ) that causes global warming during incineration. Furthermore, there is a problem that environmental pollutants such as dioxins derived from salt and incineration ash are generated.

  On the other hand, Patent Literature 1 and Non-Patent Literature 1 propose a method of treating shellfish waste by methane fermentation. The apparatus for treating methane fermentation of shellfish waste disclosed in Patent Document 1 will be described with reference to FIG. 8 to the extent necessary for understanding the present invention. The processing apparatus 31 in the illustrated example has a high-pressure separator 32 that separates shellfish waste into shellfish paste A and crushed shell C, and the remaining shellfish on the crushed shell C from the high-pressure separator 32 is removed from the remaining shellfish solution A ′. And a methane fermentation tank (bioreactor) 34 for performing methane fermentation treatment of the shellfish paste A from the high-pressure separator 32 and the remaining shellfish solution A ′ from the cleaning unit 33 (see FIG. (See Figure (A)).

  As shown in FIG. 8B, the high-pressure separator 32 defines a pressurizing chamber 32a by a pair of pistons 32d and 32e in the cylinder 32c, and the inner peripheral surface of the cylinder 32c and the piston connected to the pressurizing chamber 32a. A gap 32b for forming a shellfish paste is formed between the peripheral recess 32f of 32e and the pistons 32d and 32e are driven by a pressurizing means (for example, a hydraulic unit) 32g to remove shellfish waste and shellfish paste A. The crushed shell C is separated and discharged from the outlet 2h and the outlet 2i. Since the remaining crushed shell C has residual organic matter such as shellfish paste A and seaweed, the crushed shell C is washed with an alkaline aqueous solution or the like in the washing unit 33, and the remaining shell meat C or other organic matter on the crushed shell C is washed. Is recovered as a residual shellfish solution A ′. The methane fermenter 34 has a fixed bed carrier 27 to which methane fermentation microorganisms are attached, and the shellfish paste A and the remaining shellfish solution A ′ are both bio-biologic at a temperature at which the microorganisms are active (eg, 37 ° C. or 55 ° C.). Decomposes into gas G and digestive fluid D.

According to the processing apparatus of FIG. 8, shellfish A can be stably methane-fermented while preventing clogging with shell C, and 80% or more of shellfish paste A and residual shellfish solution A ′ are biogas G. Can be broken down into The biogas G contains 60 to 70% methane (CH ₄ ) and 30 to 40% CO _{2, and} can be supplied to, for example, a gas generator or a fuel cell to recover electric power and thermal energy (bioenergy). . Therefore, shellfish waste can be treated at a lower running cost than the conventional incineration disposal or the like by the treatment apparatus of the illustrated example. Further, in those without increasing the CO ₂ on a global scale even when returning a CO ₂ atmospheric CO ₂ is that originally secured the shellfish in the biogas G to the atmosphere (carbon neutral CO ₂₎ In addition, environmental pollutants such as dioxins are not generated in methane fermentation, and shellfish waste can be treated while keeping the environmental load small.

JP 2000-033358 A Japanese Patent No. 3397546 JP-A-11-319765 Sumio Imai et al., “High-temperature methane fermentation treatment of shellfish adhering to power plant intakes”, Journal of Electric Power Engineering Association, No.284, November 1999 Satoshi Iizuka et al. “New carbon dioxide fixation process using waste concrete” Chemical Engineering, Vol.28, No.5, September 2002 M. Kakizawa et al., "ANew CO2 Disposal Process via Artificial Weathering of Calcium SilicateAccelerated by Acetic Acid", Energy, VOL.26, pp.341-354, 2001

However, the methane fermentation treatment method for shellfish waste shown in FIG. 8 targets shellfish A which is an organic matter among shellfish wastes, and there is a problem that a large amount of shellfish C which is inorganic remains after the treatment. is there. The main component of the shell C is calcium carbonate (CaCO ₃ ), and it has been used effectively as feed and fertilizer for a long time. Recently, it has been tried to use it as a ground improvement material, a building material, and the like. However, the quality of shells generated as waste is not stable and often cannot be used or utilized effectively as feed or fertilizer. The actual situation is that the shell C that cannot be effectively used / utilized must be disposed of as waste, which increases the environmental load. In order to effectively use shellfish waste as unutilized biomass, it is desired to develop a technique for treating not only shellfish A, which is an organic matter, but also calcium lump C such as shellfish with a small environmental load.

  Accordingly, an object of the present invention is to provide a system for treating calcium lumps together with organic waste with a small environmental load.

The inventor has paid attention to the fact that waste concrete blocks (main components are calcium silicate CaSiO ₃ and calcium hydroxide Ca (OH) ₂ ), which are calcium-based inorganic compounds, dissolve in an acidic aqueous solution. For example, Patent Document 3 discloses a method for treating concrete waste in which a crushed concrete block is brought into contact with CO ₂ gas, and then immersed in an aqueous CO ₂ solution and then separated into solid and liquid and recovered as CaCO ₃ . Non-Patent Document 2 discloses that after extracting and dissolving calcium by blowing CO ₂ gas into a concrete block dispersed in water under high pressure conditions (for example, about 3.0 MPa≈30 atm), normal pressure ( The CO ₂ fixation process in which CaCO ₃ is precipitated by returning to atmospheric CO ₂ partial pressure ≒ 36Pa) has been reported (see Equations (1) and (2)). Further, Non-Patent Document 3 shows that when calcium ions (Ca ²⁺ ) are eluted from a concrete block, the dissolution rate of Ca ²⁺ from the concrete block is promoted by adding acetic acid or the like together with CO ₂ gas. (Refer to formulas (3) and (4)). According to the inventor's preliminary experiment, it is also possible to dissolve calcium blocks C such as shells using a CO ₂ aqueous solution.

[Chemical 1]
CaSiO ₃ + CO ₂ → CaCO ₃ + SiO ₂ ……………………………………………………… (1)
Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O ……………………………………………………… (2)
_{CaSiO 3 + 2CH 3 COOH → Ca} 2+ + 2CH 3 COO - + H 2 O + SiO 2 ................................. (3)
^{_{Ca 2+ + 2CH 3 COO - +}} + CO 2 + H 2 O → CaCO 3 2CH 3 COOH .................................... (4)

The present inventor also noted that the CO ₂ gas and acetic acid used for dissolving the waste concrete lump are obtained as methane fermentation treatment effluent from organic waste A such as shellfish. As described above, biogas G containing CO ₂ is generated in the methane fermentation treatment, and normally CO ₂ is returned to the atmosphere. Therefore, this CO ₂ can be used for dissolving calcium clot C such as shells. it can. In addition, digestive fluid D generated by methane fermentation contains acetic acid and other organic acids, which are usually purified and discharged in a secondary treatment facility, but this organic acid is promoted to dissolve calcium lump C. If used, the supply of medicine or the like from the outside becomes unnecessary. That is, if calcium lump C is dissolved using CO ₂ and organic acid discharged from methane fermentation, the amount of chemicals and energy input from the outside is minimized, and the organic waste A, which is biomass, is multistage. It can be expected that the calcium lump C will be treated. The present invention has been completed as a result of research and development based on this idea.

Referring to the embodiment of FIG. 1, one embodiment of a system for treating organic waste containing calcium lump according to the present invention separates calcium lump C from organic waste A containing calcium lump C. Organic waste A is decomposed into biogas G and digestive fluid D by methane fermentation, and the separated calcium lump C is stored in the storage tank 2 together with the high-pressure aqueous solution of carbon dioxide CO ₂ in biogas G and / or the digestive fluid D. It is made by adding and dissolving.

In addition, referring to the embodiment of FIG. 2, another embodiment of the organic waste treatment system containing calcium lumps according to the present invention is an organic waste A containing calcium lumps C converted into a high-pressure aqueous solution of carbon dioxide CO ₂ . In addition, the calcium lump C is dissolved in the storage tank 2 and the organic waste A remaining after the dissolution is decomposed into biogas G and digestive fluid D by methane fermentation, and carbon dioxide CO ₂ in the biogas G and / or Alternatively, the digestive juice D is returned to the storage tank 2.

Preferably, as shown in FIG. 3, the storage tank 2 is divided into a descending portion 12 and a rising portion 13 that are connected to each other at the bottom end by a vertical partition wall 11 so that carbon dioxide CO ₂ can be dissolved in water at the bottom end. And the organic waste A containing the calcium lump C or the calcium lump C separated from the organic waste A is introduced into the top of the descending section 12, and carbon dioxide CO ₂ in the biogas G And / or the digestive juice D is supplied to the bottom end vicinity. In this case, the discharge channel 14 communicating with the water area 20 in the environment is provided in the ascending portion 13 of the deep reservoir 2a, and the dissolved solution K of the calcium block C can be discharged into the water area 20 in the environment. Further, as shown in FIG. 4, a methane fermentation tank 1 is provided in the vicinity of the top end of the rising portion 13 of the deep reservoir 2a, and the organic waste A remaining after dissolution is digested with the biogas G in the vicinity of the top end of the rising portion 13. It can be decomposed into liquid A.

The processing system of the organic waste A containing the calcium lump C according to the present invention is the organic waste A in the organic waste A together with the carbon dioxide CO ₂ in the biogas G discharged from the methane fermentation of the organic waste A and the digested liquid D. Since the calcium lump C is charged into the storage tank 2 and dissolved, the following remarkable effects are produced.

(A) Since the calcium lump C of waste with unstable quality can be dissolved and recovered as a solution or powder of calcium carbonate CaCO ₃ , the waste of the calcium lump C can be effectively used.
(B) Calcium lump C is dissolved using carbon dioxide CO ₂ and digestive fluid D in biogas G discharged from methane fermentation of organic waste A, so new energy and drugs from outside are introduced. Therefore, it is possible to provide a resource-saving / energy-saving processing system.
(C) Since the calcium lump C is dissolved by the multi-stage utilization of the organic waste A, which is biomass, the entire organic waste A containing the calcium lump C can be treated with a small environmental load. Processing and disposal in harmony with the environment is possible.

(D) The storage tank 2 that dissolves the calcium block C is a deep-layer storage tank 2a, and the calcium block C is dissolved by using the high pressure in the deep underground, so that the site area is reduced because it becomes a vertical shaft type. It is possible to simplify the structure of the storage tank from the ground-mounted type.
(E) It can be used for the treatment of shellfish waste, and it can be widely applied to the treatment of organic waste A including the skeleton of eggshells, bones and teeth of vertebrates such as fish and birds, and crustaceans such as crab shells. is there.
(F) Moreover, it becomes possible to return the calcium lump C in the organic waste A dissolved in carbon dioxide to the environment, and when the organism recaptures the calcium lump C returned to the environment during the growth process, It can be expected to contribute to a new material cycle of calcium and carbon dioxide in

FIG. 1 shows an embodiment in which the treatment system of the present invention is applied to shellfish waste, which is an example of organic waste A containing calcium lump C. However, the application target of the present invention is not limited to shellfish waste, and can be widely applied to organic waste A containing calcium blocks C such as eggshell, vertebrate bone, and crustacean exoskeleton. The treatment system of the illustrated example is a sorter 6 for separating shellfish waste (A + C) into organic waste (shellfish) A and calcium lump (shell) C, and the separated organic waste A by methane fermentation treatment. Methane fermenter 1 that decomposes into biogas G and digestive fluid D, methane concentrator 3 that removes CO ₂ from biogas G generated in methane fermenter 1, CH ₄ from which CO ₂ has been removed is converted into energy It has the secondary processing facility 8 which purifies the digestive liquid G generated in the energy conversion device 4 and the methane fermentation tank 1.

As with the high-pressure separator 32 described above with reference to FIG. 8, the separator 6, for example, presses shellfish waste (A + C) into organic waste A and hard calcium lump C that are crushed into minced shapes. It can be separated. The crushed shell cleaning unit 33 of FIG. 8 may be included in the sorter 6. The organic waste A separated from the calcium block C by the sorter 6 is decomposed into biogas G containing about 66% CH ₄ and about 33% CO ₂ by the methane fermentation bacteria in the methane fermentation apparatus 1. A part is decomposed into digestive juice D containing organic acids (molecular formula model R-COOH) such as formic acid, acetic acid, propionic acid, n- and i-butyric acid, n- and i-valeric acid, and lactic acid (formula (11) reference).

[Chemical 2]
C _x H _y O _z (Organic) → aCH ₄ + bCO ₂ + cH ₂ O ……………………………………… (11)
66% × CH ₄ + 33% × CO ₂ + 66% × 2O ₂ → CO ₂ + 66% × 2H ₂ O ……………………… (12)
CO ₂ + H ₂ O → H ₂ CO ₃ → HCO ₃ ⁻ + H ⁺ ………………………………………………… (13)
^{_{CaCO 3 + HCO 3 - + H}} + → Ca (HCO 3) 2 → Ca 2+ + 2HCO 3 - .................................... (14)
_{CaCO 3 + 2R-COOH → Ca} 2+ + 2R-COO - + HCO 3 - + H + .................................... (15)

The biogas G generated in the methane fermentation apparatus 1 removes CO ₂ in the methane concentrator 3 and concentrates CH ₄ to about 98%, for example, and then converts it into electric power and thermal energy in the energy conversion apparatus 4 such as a fuel cell. Convert. However, the methane concentrator 3 is not essential for the present invention. For example, when the energy converter 4 is a gas generator or a gas boiler, the biogas G generated in the methane fermentation apparatus 1 is supplied to the energy converter 4. It can be directly introduced, and CH ₄ can be burned and converted into electric power and thermal energy (see equation (12)). The digestive fluid D generated in the methane fermentation apparatus 1 is sent to the secondary treatment facility 8, and after being subjected to a purification process for organic acids, it can be discharged as treated water W into sewers, rivers, sea, groundwater, and the like.

Moreover, the processing system of the example of illustration has the storage tank 2 which takes in and dissolves the calcium lump C sorted by the sorter 6. An example of the storage tank 2 is preferably a pressure vessel having a stirring device 5. For example, fresh water such as treated water W of the secondary treatment facility 8 is charged into the storage tank 2 together with the calcium block C, and CO ₂ generated from the biogas G in the methane concentrator 3 and the energy converter 4 is stirred while being stirred by the stirrer 5. Supply under high pressure. By increasing the partial pressure of CO ₂ in the gas phase in the storage tank 2 (see (13)) by dissolving CO ₂ supplied to the water and bicarbonate ion, in the main component of the calcium mass C in this case Certain CaCO ₃ can be dissolved as Ca ²⁺ by bicarbonate ions (see equation (14)).

Further, in the illustrated system, a part of the digestive fluid D generated in the methane fermentation apparatus 1 is also supplied to the storage tank 2 via the secondary treatment facility 8. Since the reaction rate of the dissolution reaction of CaCO ₃ (equation (14)) is low, the partial pressure of CO ₂ in the gas phase in the storage tank 2 is used to treat the calcium clot C in the storage tank 2 of a limited size. It is necessary to increase the reaction rate by increasing the reaction rate, but by adding an organic acid such as acetic acid in the storage tank 2, the dissolution reaction of CaCO ₃ can be further accelerated (see equation (15) and Non-Patent Document 3). ). In addition, the digested liquid D may contain as a residue calcium lumps C such as crushed shells that cannot be decomposed in the methane fermentation tank 1, but according to the treatment system of the illustrated example, such residual calcium lumps C are digested. It can be introduced into the storage tank 2 together with the liquid D and dissolved.

The calcium clot C dissolved in the storage tank 2 can be taken out from the storage tank 2 as a calcium solution K and recovered by, for example, returning to normal pressure to precipitate CaCO ₃ . Calcium lump C such as shells with unstable quality can be expected to be effectively used as a raw material for fine sand and recycled concrete by using powdered CaCO ₃ . The calcium solution K after the recovery of CaCO ₃ contains the organic acid supplied via the secondary treatment facility 8, and the calcium solution K after the recovery of CaCO ₃ is returned to the methane fermentation apparatus 1 as necessary. The organic acid can be converted to biogas G and recycled again. In addition, by returning the calcium solution K to the methane fermentation apparatus 1, calcium necessary for the growth of the methane fermentation microorganisms can be supplied.

That is, in the present invention, the entire organic waste A including the calcium lump C is efficiently obtained by circulating the CO _2, digestive juice D, and calcium solution K between the methane fermentation apparatus 1 and the storage tank 2. It is also possible to process in multiple steps. In addition, as will be described later, the calcium solution K from the storage tank 2 is discharged into the water area in the environment such as the sea floor, the bottom of the lake, or the ground water together with the CO _{2 in the} form of bicarbonate ions while maintaining the high pressure. It can also be used for conservation. As will be described later, may be insufficient CO ₂ is supplied to the reservoir 2, it is also possible to circulate back the CO ₂ in the calcium solution K in the storage tank 2.

FIG. 5 is a trial calculation of the material balance and energy balance when shellfish waste generated in a fish processing facility is treated by the treatment system of the present invention. For example, if one ton of organic waste A shellfish is treated with methane, about 53 Nm ³ of biogas G can be recovered. By burning this biogas G, about 87 kwh (53 Nm ³ × 1.65 kwh) Energy and about 0.104 tons of CO ₂ gas are obtained. When all of this is bicarbonate ionized, 0.23 tons of CaCO ₃ , which is the main component of the shell of calcium lump C, can be dissolved. In addition, the energy required for the CaCO ₃ dissolution reaction of the formula (14) is considered to be about 77.2 to 24 kwh per ton of CaCO _{3 in} consideration of shell crushing conditions and the like.

As shown in Fig. 5, an aquatic processing facility that generates 510 tons / month of shellfish produces about 45000 kwh / month (≒ 510 × 87) energy and about 53 tons / month (≒ 510 × 0.104) of CO ₂ gas. The shell can dissolve 120 tons / month (≒ 510 × 0.23). The energy required for the dissolution reaction of 120 tons / month of shells is about 9300 to 3000 kwh / month. Therefore, if the ratio of the organic waste A to the calcium lump C is about 4.3 times or more, the calcium lump C using the carbon neutral CO ₂ in the biogas G and the combustion energy of the biogas G. It is possible to dissolve the entire amount.

FIG. 6 is a trial calculation of material balance and energy balance when shellfish waste generated in a large power plant of 5 million kw class is treated by the treatment system of the present invention. Shellfish waste generated at a power plant or the like has a relatively small ratio of organic waste A to calcium lump C, so that CO ₂ alone in biogas G may be insufficient to dissolve calcium lump C. For large power plants in the illustrated example, can only dissolve shells of approximately 8.1 t / month in the CO ₂ gas in the biogas G can be recovered from the shellfish flesh 35 tons / month (≒ 35 × 0.23), about 25 ton / month Only less than 40% of the generated shell can be dissolved. In this way, when CO ₂ in the biogas G is insufficient, a part (about 60% in the illustrated example) of bicarbonate ions in the calcium solution K discharged from the storage tank ₂ is recovered as CO ₂ and stored. The shortage of CO ₂ can be compensated by returning to tank 2 and circulating.

FIG. 7 shows substances in the case where a residue containing calcium clots C such as eggshells and shells deposited on the bottom of the methane fermentation apparatus 1 is treated with the treatment system of the present invention in the methane fermentation treatment of garbage such as straw waste. This is a trial calculation of the balance of payment and energy balance. The calcium block C extracted from the bottom of the methane fermentation apparatus 1 is introduced into the storage tank 2 together with the digestion liquid D and dissolved. In methane fermentation of raw garbage containing various organic components, biogas G of 160Nm ³ or more per ton of garbage can be recovered, and more energy and CO ₂ gas can be obtained than methane fermentation of shellfish. It is done. Moreover, the calcium lump C contained in the raw garbage is about 5%. For example, the calcium contained in the raw garbage using CO ₂ from the methane concentrator 3 and bioenergy from the energy converter 4 is used. The entire amount of the mass C can be sufficiently dissolved. Moreover, the calcium solution K discharged | emitted from the storage tank 2 can be discharged and discarded, diluting to a sewer.

  Thus, it is possible to achieve the “system for treating calcium lumps together with organic waste with a small environmental load”, which is an object of the present invention.

FIG. 2 shows another embodiment of processing shellfish waste using the processing system of the present invention. The treatment system of the illustrated example omits the sorter 6, shellfish waste (A + C) is directly charged into the storage tank 2 to dissolve the calcium clot C, and the organic waste A remaining after dissolution is transferred to the methane fermentation tank 1. The CO ₂ in the biogas G generated in the methane fermentation tank 1 is returned to the storage tank 2 via the methane concentrating device 3 and the energy conversion device 4, and then decomposed into the biogas G and the digestive fluid D. 1 is returned to the storage tank 2 via the secondary treatment facility 8. That is, by using the storage tank 2 that dissolves the calcium lump C, shellfish waste and shellfish can be separated. In the separation processing of shellfish and shells by the sorter 6 as shown in FIG. 1, there is a possibility that ground shells and the like enter the methane fermentation tank 1 together with shellfish and block the fixed bed carrier 27. By dissolving the shell in the storage tank 2 and separating it from the shellfish, the fixed bed carrier 27 can be prevented from being blocked and the efficiency of the system can be improved by omitting the sorter 6.

FIG. 3 shows an embodiment of the present invention in which the storage tank 2 in the embodiment of FIG. 1 or FIG. 2 is a deep-type storage tank 2a using high pressure in the deep underground. The deep storage tank 2a in the illustrated example has a pressure at which CO ₂ dissolves in water at the bottom end, and is partitioned by a vertical partition 11 into a descending portion 12 and an ascending portion 13 communicated at the bottom end. For example, by providing the descending part 12 and the ascending part 13 that reciprocate to about 300 m below the ground, it is possible to obtain a pressure of about 3.0 MPa necessary to dissolve the calcium lump C by dissolving CO ₂ in water at the bottom end. it can. The deep reservoir 2a in the illustrated example is provided alongside a bioenergy recovery facility 9 including the methane fermentation tank 1 on the site of a large power plant adjacent to the ocean, which is the water area 20, and is a deep reservoir. A discharge channel 14 communicating with the ocean via a filter 15 is provided in the ascending portion 13 of 2a. In place of or in addition to the filter 15, a suitable sedimentation tank (not shown) or the like may be provided in the discharge channel 14.

In the illustrated example, fresh water such as treated water W from the bioenergy recovery facility 9 is filled into the deep reservoir 2a, and the organic waste A containing calcium lumps C is added to the top of the descending portion 12 of the deep reservoir 2a. It is thrown into. In addition, the CO ₂ in the biogas G generated in the bioenergy recovery facility 9 is supplied to the vicinity of the bottom of the descending portion 12 deeper than the CO ₂ solubilization zone of the deep reservoir 2a through the gas transport path 17 and the gas branch path 18. The digestive juice G or treated water W generated in the bioenergy recovery facility 9 is supplied to the bottom end of the deep reservoir 2a through the liquid transport path 19.

As in the conventional deep shaft process, the ascending unit 13 and the descending unit 12 of the deep reservoir 2a may be provided with, for example, an aeration device or a circulation pump at the upper part of the ascending channel 13 to form an upflow and a downflow. it can. The CO ₂ supplied to the descending portion 12 of the deep reservoir 2a is guided to the bottom of the reservoir 2a by the descending flow and melts in water by water pressure to dissolve the calcium block C. A part of the calcium solution K containing bicarbonate ions and Ca ²⁺ dissolved in water is combined with the organic waste A that is not dissolved in water by the filter 15 provided in the ascending part 13 or the precipitation tank provided in the discharge channel 14. It is separated and discharged into the deep ocean through the discharge channel 14. The released bicarbonate ions and Ca ²⁺ diffuse while maintaining the bicarbonate ion form due to water pressure, and are incorporated into marine organisms during the growth process, creating a new material cycle of calcium and carbon dioxide. Contribute to conservation. Instead of the ocean, the calcium solution K can be discharged into the water area 20 in an environment such as a lake or groundwater, and used for the conservation of the lake or groundwater environment.

The organic waste A remaining in the deep reservoir 2a is recovered together with the calcium solution K at the top end of the ascending portion 13 by using the ascending force of CO ₂ in the CO ₂ foaming zone of the ascending portion 13. Since the calcium solution K returns to the atmospheric pressure on the ground, CO ₂ is separated and CaCO ₃ is precipitated as microcrystals, so that the CaCO ₃ can be recovered and used. The calcium solution K after the recovery of CaCO ₃ is sent to the bioenergy recovery facility 9 together with the organic waste A, and used for methane fermentation in the methane fermentation tank 1. If necessary, a part of the bicarbonate ions in the calcium solution K is recovered as CO ₂ and returned to the top end of the descending portion 12 of the storage tank 2 and circulated.

For example, the deep storage tank 2a is sized to store one month to one year of shellfish waste generated at a large power plant, and the bottom end of the deep storage tank 2a according to the amount recovered from the top of the ascending section 13 The digestive juice G or treated water W is supplied to the deep-sea storage tank 2a to store the shellfish waste for 1 month to 1 year and dissolve the shell. When organic waste A or the like settles and accumulates at the bottom of the deep reservoir 2a, it sinks to the bottom by vigorously ejecting CO ₂ to the bottom of the reservoir 2a via the backwash nozzle 17a. Return organic waste A etc. to the upward flow and collect it.

  FIG. 4 shows a methane fermentation tank 1 provided with a fixed bed carrier 27 for methane fermentation microorganisms in the vicinity of the top of the ascending portion 13 of the deep reservoir 2a. The deep reservoir 2a and the methane fermentation tank 1 are combined together. An embodiment in which the organic waste A is decomposed into biogas G and digestive fluid A in the vicinity of the top end of the rising portion 13 will be described. The fixed bed carrier 27 can be the same as that installed in the conventional methane fermentation tank 1.

In the illustrated example, a CO ₂ recovery device 26 which is bubbled at the central portion and the outer peripheral portion of the ascending portion 13 is provided below the fixed bed carrier 27 of the methane fermentation microorganisms, and the recovery device 26 collects the bubbles and the recovery device 26. The calcium solution K and the organic waste A that have passed through are introduced into the fixed bed carrier 27. Preferably, an injection path 19 for dilution and pH adjustment is provided below the fixed bed carrier 27, and the digested liquid D above the fixed bed carrier 27 or the treated water W from the secondary treatment facility 8 is passed through the injection path 19. By injecting below the fixed bed carrier 27, the organic substance concentration and pH in the calcium solution K introduced into the fixed bed carrier 27 are adjusted.

  Further, a biogas recovery device 28 is provided above the fixed bed carrier 27 of methane fermentation microorganisms, and the biogas G generated in the fixed bed carrier 27 is recovered and sent to the energy conversion device 4. As shown in the figure, by providing a fixed bed carrier 27 at the top end of the ascending portion 13 of the deep reservoir 2a, shell solubilization treatment and shellfish methane fermentation treatment are performed in parallel, including calcium clot C. More efficient treatment of organic waste A can be expected.

As mentioned above, although the processing method of the organic waste A containing the calcium lump C was demonstrated, it is also considered that the processing system of this invention is applied to the process of calcium lump C, such as waste concrete. That is, a storage tank 2 that takes in and dissolves waste concrete blocks and a methane fermentation tank 1 are provided side by side, and CO ₂ and digestive fluid G in the biogas G generated in the methane fermentation tank 1 are supplied to the storage tank 2 and discarded. Melt concrete. For example, waste concrete lump is thrown into the top end of the descending part 12 in the deep reservoir 2a of FIG. 3, and CO ₂ in the biogas G generated in the methane fermentation tank 1 and digestive fluid at the bottom of the deep reservoir 2a. G is supplied. By dissolving the waste concrete lump using CO ₂ and digestive fluid D discharged from the methane fermentation tank 1, the waste concrete can be treated by multi-stage use of the organic waste A that is biomass, and the global environment It can be a resource-saving and energy-saving waste concrete treatment system in harmony with the environment.

It is explanatory drawing of one Example of this invention. It is explanatory drawing of the other Example of this invention. It is explanatory drawing of the Example of this invention using a deep type storage tank. It is explanatory drawing of the Example of this invention which incorporated the methane fermentation tank in the deep-layer type storage tank. It is explanatory drawing of the Example which applied this invention to the processing of the shellfish waste of a fishery processing facility. It is explanatory drawing of the Example which applied this invention to the processing of the shellfish waste of a large sized power station. It is explanatory drawing of the Example which applied this invention to the process of the organic waste containing the calcium lump in a garbage disposal facility. It is explanatory drawing of the processing method of the conventional shellfish waste.

Explanation of symbols

1 ... Methane fermentation tank (bioreactor)
2 ... Storage tank (storage pit) 2a ... Deep-layer storage tank 3 ... Methane concentrator 4 ... Energy converter (power generator)
5 ... Agitator 6 ... Separator 7 ... Gas holder 8 ... Secondary treatment facility 9 ... Bio-energy recovery facility
10 ... Peripheral wall 11 ... Bulkhead
12 ... Descent part 13 ... Rising part
14 ... Release channel 15 ... Filter
17 ... Gas transport path 18 ... Gas branch path
19 ... Liquid transport route
20 ... Sea 21 ... Ground
22… Power plant 23… Intake facility
24… Intake channel 25… Drain channel
26 ... CO2 recovery device 27 ... Fixed bed carrier
28… Biogas recovery device 29… Injection path
31… Methane fermentation treatment equipment 32… High pressure sorter
32a… Pressure chamber 32b… Gap
32c… Cylinder 32d… Upper piston
32e… Lower piston 32f… Recess
32g… Hydraulic unit 32h… Outlet
32i ... Payout port 32j ... Payout piston
32k ... Shell inlet 33 ... Shell cleaning unit
33a… Washing tank 33b… Solid-liquid separator
33c… Crushing shell circulation pump 33d… Vibrating sieve
33e… Washing water pump
34… Methane fermentation tank 35… Crusher
36… Slurry tank 37… Slurry supply pump
38 ... Slurry circulation pump 39 ... Secondary treatment tank
40… Immersion membrane 41… Aeration blower
42 ... treated water pump 43 ... desulfurizer
44 ... Gas holder 45 ... Cleaning hopper A ... Organic waste (shellfish paste)
A '... residual shellfish solution C ... calcium lump (crushed shell)
D ... Digestive fluid E ... Energy G ... Biogas K ... Calcium solution S ... Seawater W ... Treated water

Claims (6)

  Separating calcium lump from organic waste containing calcium lump, separating the organic waste after separation into biogas and digestive fluid by methane fermentation, and separating the separated calcium lump into high pressure aqueous solution of carbon dioxide in biogas And / or an organic waste treatment system containing calcium lumps that are dissolved in a storage tank together with a digestive fluid.   An organic waste containing calcium lump is put into a storage tank together with a high-pressure aqueous solution of carbon dioxide to dissolve the calcium lump, and the organic waste remaining after dissolution is decomposed into biogas and digestive juice by methane fermentation, An organic waste treatment system containing calcium lumps obtained by returning carbon dioxide and / or digestive fluid in gas to a storage tank.   The system according to claim 1 or 2, wherein the storage tank is a deep-type storage tank in which a pressure at which carbon dioxide dissolves in water is obtained at the bottom end and is partitioned into a descending part and a rising part communicated at the bottom end by a vertical partition. The calcium lump separated from the organic waste or the organic waste containing the calcium lump is put into the top of the descending part, and carbon dioxide and / or digestive juice in the biogas is supplied near the bottom end. An organic waste treatment system containing calcium lumps.   The system according to claim 3, wherein a release channel communicating with a water area in the environment is provided at an ascending portion of the deep reservoir, and the organic substance contains a calcium mass formed by discharging the solution of the calcium mass to the water area in the environment. Waste treatment system.   The system according to claim 3 or 4, wherein a methane fermentation tank is provided in the vicinity of the top end of the rising portion of the deep-layer storage tank, and the organic waste remaining after the dissolution is decomposed into biogas and digestive fluid in the vicinity of the top end of the rising portion. Organic waste processing system containing calcium lumps.   6. The system for treating an organic waste containing a calcium lump according to claim 1, wherein the organic waste containing the calcium lump is shellfish waste.

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